Comparison of odor sub-maps defined by different activation levels. a) The butanal odor map (C4) was divided into lower (L50) and upper (H50) halves by thresholding at 50th intensity percentile. The H50 was then divided into three levels: I1, 84-100% (highest intensity), I2, 67-83% (medial intensity), I3, 50-66 % (low intensity). b) Example to demonstrate the analysis of spatial correlation (SCC; see Materials and Methods) between sub-maps for different odors: A is the I1 sub-map for C4 and B is the I1 sub-map for C5. The SCC value is calculated from the total counts of the four different pixel categories, N[1,1], N[1,0], N[0,1] ,and N[0,0], represented by red, black, green, and blue, respectively. c) A detailed analysis using SCC with data in Fig. 2a. C4/C5, the comparison between more similar butanal and pentanal maps; Cn/Cn+1, averaged values for all comparisons between the maps of aldehydes with one carbon difference (n = 4, 5, 6, and 7). C4/C8, the comparison between less similar butanal and octanal maps; and Cn/Cm, averaged values for all possible comparisons between the maps of aldehydes shown in Fig. 2a (m, n = 4, 5, 6, 7, and 8; m!=n). I1nI1 (black bars), I1nI2 (red bars), I1nI3 (green bars), and I1nL50 (blue bars) are for comparisons of I1 sub-map of one odorant with the I1, I2, I3, and I50 sub-map of another odor-map, respectively; I2nI2 (orange bars), the comparisons between the I2 sub-maps of different odor-maps; and I3nI3 (indigo bars), the comparisons between the I3 sub-maps of different odor-maps. The dotted yellow lines around SCC values of +/- 0.2 depict the significant correlation at p = 0.01. d) Tests of reproducibility of activity patterns for aldehydes using the SCC calculation. Reproducibility was assessed from SCC values at three different thresholding levels: top 50% (H50nH50), top 33% (H33nH33) and top 16.7% (I1nI1). The plotted values represent the averaged SCC from pentanal to octanal.

This database was supported by the Human Brain Project (NIDCD, NIMH, NIA, NICD, NINDS) and MURI (Multidisciplinary University Research Initiative). It is now supported by RO1 DC 009977 from the National Institute for Deafness and other Communication Disorders.